EtherTen running hot

The EtherTen combines an Uno-equivalent Arduino-compatible board and Wiznet-based Ethernet support, along with a microSD card slot and Power-over-Ethernet support. [Product page]
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jonoxer
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Re: EtherTen running hot

Post by jonoxer » Tue Mar 26, 2013 11:05 am

USB power definitely bypasses the onboard regulator, but the voltage can still be marginal sometimes because of voltage drop across the USB cable.

One of the major sources of heat on both the EtherTen and the EtherMega isn't the voltage regulator: it's the Wiznet Ethernet chip! The W5100 is well known for running really hot even in normal operation. If you search for "W5100 hot" you'll find more than a couple of references.
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Re: EtherTen running hot

Post by effgee » Thu Mar 28, 2013 11:42 am

thanks Jon

I agree the heat appears to be coming from the wiznet chip, but I've never noticed an ethermega glowing like my etherten seems to...

will have to take more notice next time.

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Re: EtherTen running hot

Post by andrewr » Fri Aug 02, 2013 11:40 am

jonoxer wrote:One of the major sources of heat on both the EtherTen and the EtherMega isn't the voltage regulator: it's the Wiznet Ethernet chip! The W5100 is well known for running really hot even in normal operation.
Just started playing with an EtherTen today and I will agree with you Jon, that yes, the W5100 runs hot....

... but so does the regulator!!!! I've got it running from a 12v regulated wall wart via DIY POE and I cannot hold my finger on the regulator.

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Re: EtherTen running hot

Post by jonoxer » Fri Aug 02, 2013 12:01 pm

Yes, 12V is at the upper end of what you'd want to run. The EtherTen has a linear voltage regulator that sheds excess power as heat, and it runs at 5V so it needs to shed 7V from a 12V supply. I don't have an EtherTen in front of me to measure, but if it consumes (say) 200mA for the board itself plus whatever else is plugged into it, and P = VI, so the power dissipated will be 7 x 0.2 = 1.4W. That's a lot of heat coming out of a small device, so it'll get quite hot.

For EtherTens that I run on DIY POE, I try to have about 9 to 10V on the wire at the device end. It's high enough to give the voltage regulator some headroom, but not high enough to make it run hot. Better still, either an EtherMega (which uses a switchmode power supply) or a PR28V module helps reduce the temperature.
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Re: EtherTen running hot

Post by andrewr » Fri Aug 02, 2013 12:18 pm

Cheers Jon.

I might go down the path of a 9v regulated wall wart me thinks.

First time I've played with any sort of Arduino and am having a ball so far :-)

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Re: EtherTen running hot

Post by jonoxer » Fri Aug 02, 2013 12:32 pm

I'm glad you're having fun! I'd be very interested to see what you're doing, so if you get a chance to do a blog post or put up some photos I'd love to see them.

Depending on what you're doing with the EtherTen it can be a bit of a juggling act getting the supply voltage right. For example, I have a few EtherTens with relays attached for remote control of different devices. Because the relays cause sudden voltage drops when they power on, it can be a fine line between having the supply voltage high enough to avoid brown-outs of the Arduino when the relays fire and being low enough to stay reasonably cool. A big electrolytic capacitor (like 470uF or so) between 5V and GND on the EtherTen can help make it less susceptible to flaky supply voltage.
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Re: EtherTen running hot

Post by andrewr » Sun Aug 11, 2013 1:07 am

Nothing exciting Jon, just using the EtherTen and two HUMID sensors to monitor indoor and outdoor temps. The sketch on the EtherTen just serves up a real simple web page which a perl script running on my server interrogates every 5 minutes. The results are then graphed using MRTG to produce some nice looking graphs.

As I said nothing overly exciting, just something to keep my grey matter ticking over and the chance to learn a bit of PERL and Arduino sketch writing.

cheers, Andrew
Last edited by andrewr on Mon Aug 12, 2013 7:33 am, edited 1 time in total.

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Re: EtherTen running hot

Post by jonoxer » Sun Aug 11, 2013 7:00 am

That's cool. I like the way you're using MRTG to plot the data.
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Re: EtherTen running hot

Post by Maj » Thu Jan 09, 2014 5:46 am

Hello Freetronics and friends. I can see that many people are having a problem with EtherTen regulators running hot. I'm yet another one.

I bought a couple of these to run on a project that needs a 12v source due to other equipment, but I can't image that they'll survive very long at that temperature.

I've already destroyed one due to the misleading screen printing on the board. (It says "PoE 7-48v". Oh no it isn't! ;) I later read online that it only supports 7-12V over PoE)

Can anyone else confirm if they have had success (or failure) leaving these running with a 12 volt supply for any length of time? Was it ventilated/sealed case?

Maj

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Re: EtherTen running hot

Post by andrew » Thu Jan 09, 2014 9:31 pm

Maj wrote:Hello Freetronics and friends. I can see that many people are having a problem with EtherTen regulators running hot. I'm yet another one.

I bought a couple of these to run on a project that needs a 12v source due to other equipment, but I can't image that they'll survive very long at that temperature.

I've already destroyed one due to the misleading screen printing on the board. (It says "PoE 7-48v". Oh no it isn't! ;) I later read online that it only supports 7-12V over PoE)

Can anyone else confirm if they have had success (or failure) leaving these running with a 12 volt supply for any length of time? Was it ventilated/sealed case?

Maj
As others have mentioned, they do run hot. If placed in an enclosure, ensure it has ventilation holes. The PoE section is for one of our optional adaptors - for example:
http://www.freetronics.com/collections/ ... tor-8023af
I have sent you a direct message.

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